Centrifugal switch



Oct. 6,1970 G. A HACKBARDT 3,532,841

' CENTRIFUGAL SWITCH Filed Deo. 9, 1968 United States Patent IO 3,532,841 CENTRIFUGAL SWITCH George A. Hackbardt, Owosso, Mich., assignor to Controls Company of America, Melrose Park, Ill., a corporation of Delaware Filed Dec. 9, 1968, Ser. No. 782,102 Int. Cl. H01h 35/10 U.S. Cl. 200-80 7 Claims ABSTRACT OF THE DISCLOSURE A switch actuating member has, in a one-piece member molded of resilient material such as polypropylene, a central hub, angularly spaced weight bodies, and web sections connecting the weight bodies to the hub. The hub is connectable to a rotating member and, as a result of rotation, the 'weight bodies react against a frame to produce axial movement of the hub. The axial hub movement is used to control a switch.

BACKGROUND OF INVENTION I.-Field of invention This invention relates to centrifugal switch .arrangements and, more particularly, to the construction of a centrifugal actuator in such arrangements.

II.-Discussion of prior art Centrifugal switches are well-known and various constructions and arrangements have been proposed in the past. Some of the common shortcomings of prior proposed arrangements have been relatively complex structures and/ or lack of positive operation.

SUMMARY OF INVENTION A general object of this invention is to provide a centrifugal switch of relatively simplified construction and yet one which provides positive action.

Another object of this invention is to provide a centrifugal switch `which affords positive action with repeatable characteristics over a large number of operations.

For the achievement of these and other objects, this invention proposes an arrangement including a one-piece member made up of a plurality of weight bodies spaced L angularly relative to each other about an axis and each body being connected for joint rotation with a support portion. Preferably, the connection between the bodies and support portion is made with integral connecting webs and the support portion is connectable to a rotating member. The weight bodies are urged radially as a result of rotation and this movement is used to control a switch. Preferably, the one-piece member is supported in a frame such that the weight bodies react against the frame in being urged radially and, through the webs, impart movement to the support portion. This movement of the support portion is used to control the switch.

DESCRIPTION OF DRAWINGS FIG. 1 is a View, partially in section, of a centrifugal switch embodying this invention and connected to a piece of dynamoelectric machinery; and

FIG. 2 is an exploded view in perspective of the actuator portion of the centrifugal switch.

DESCRIPTION lOF PREFERRED IEMB ODIM'ENT With particular reference to the drawing, centrifugal switch assembly is illustrated as connected to shaft 11 of an electric motor 12. -Electrical switch 13 of the assembly can be connected in the circuit of motor 12 and, for example, can be effective to switch the motor from 3,532,841 Patented Oct. 6, 1970 ice a start to a run condition as the motor comes up to speed or to either selectively open and close the motor circuit. The switch is controlled by the actuator portion of the centrifugal switch assembly, the actuator portion being connected for rotation with the motor so as to provide switch operation on the basis of motor rotation.

In accordance with this invention, the actuator portion of the centrifugal switch assembly includes a one-piece member 14, a frame 15 and a hub 16. Hub 16 is fastened to shaft 11 by set screw 17. Frame 15 is fixed to the hub by, for example, the rolled lip illustrated at 18. Member 14 is connected to frame 15 in a manner to be described more completely hereinafter and the entire assembly consisting of the member 14, the frame and hub 16 rotate jointly with shaft 11.

Structurally, member 14 includes a central hub 20` and three weight bodies 21, 22 and 23 extending radially from the hub and spaced angularly about the axis of motor rotation. The bodies 21, 22 and 23 are each connected to hub 20 by web sections 24, 25 and 26 and the bodies are relatively large, as compared to the hub and the webs, and are preferably solid to provide a relatively large mass spaced radiallly outward of the motor axis. A preferred construction for the weight bodies is illustrated in the drawing wherein the bodies have substantial extensions in both an axial and radial direction and have substantial axially facing surfaces. Other constructions can, however, be used. As a result of motor rotation, bodies 21, 22 and 23 are urged radially outward.

As is perhaps best illustrated in FIG. 2, frame 15 includes a central section 27 to which the rolled connection with hub 16 is made. The frame also includes three arms 28, 29 and 30 which extend radially from the central section. Each arm has an axially extending, generally L-shaped end 31, 32 and 33. The free leg of each of these ends is notched at 34, 35 and 36 to provide axially facing surfaces 37, 38 and 39. Bodies 21, 22 and 23 include projections 41, 42 and `43 which, when member 14 is assembled in the centrifugal switch assembly, are engaged in notches 34, 35 and 36 respectively.

To complete the structure of the centrifugal switch assembly, it will be noted that hub 20 is in the form of an inverted, hollow cup-shaped member and receives spring 45. Spring 45 is seated between central section 27 of the frame and hub 20 and biases the hub in a direction away from the central frame section. 4Frame 15 also includes three turned ears 46, 47 and 48, these ears extend axially and are spaced angularly about the axis of rotation. Hub 20 of the one-piece member is received within the area defined by these ears so that the ears engage and guide axial movement of the hub which, in a manner now to be described, occurs as a result of rotation of shaft 11.

It should be noted that plunger 49 of switch 13 is in engagement with hub 20. In the full line position illustrated in FIG. 1 plunger 49 is preferably bottomed thereby limiting movement of hub 20 under the influence of spring 45. In this position, the motor circuit and the switch can be such that the switch establishes the starting circuit for motor 12. After the motor is started and as the motor comes up to speed, the assembly including member 14, frame 15, hub 16, and spring 45 rotates with shaft 11. This rotation tends to urge bodies 21, 22 and 23 radially outward but the bodies engaging ends 31, 32 and 33, specifically projections 41, 42 and 43 being in engagement with surfaces 37, 38 and 39, this outward movement is resisted by the frame. Thus the bodies react against the frame as a result of rotation and tend to pivot about the enagagement between projections 41, 42 and 43 and surfaces 37, 38 and 39. This pivotal movement is transmitted through webs 24, 25 and 26 to hub 20 moving the hub axially toward motor 12 against the bias of spring 45 thereby releasing plunger 49 and allowing the switch to change its state of operation and establish the run circuit for motor 12. Ears 46, 47 and 48 maintain proper alignment of hub 20 with respect to the motor shaft and the switch during this avial movement. The phantom line showing in FIG. 1 illustrates the condition of the switch plunger and the actuator portion of the centrifugal switch in the run condition. When the motor is stopped and rotation ceases, spring 45 urges the hub 20 upwardly again depressing switch plunger 49 to return the switch to the start condition and also transmitting movement through webs 24, 25 and 26 to return bodies 21, 22 and 23 to the full line position of FIG. l.

Preferably, the weight bodies, hub and connecting webs are molded as an integral, one-piece member to thereby provide, with the frame, an actuator of simple construction. Also, Webs 24, 25 and 26 are relatively thin as compared to the weight bodies and the hub so that they are capable of permitting some limited relative movement between those members while also providing an adequate structural member for transmission of forces between the hub and the weight bodies to achieve the hub, and body, movement necessary for actuation. Preferably, the onepiece member is made of a material such as polypropylene which is readily molded in the desired shape and which also can be flexed a large number of times without losing its inherent characteristics.

Throughout this description the reference to axial and radial directions is made with respect to the axis of hub 20 or the axis of rotation of the motor.

What is claimed is:

1. A centrifugal switch arrangement comprising, in combination, a one-piece member including a plurality of angularly spaced weight bodies disposed about an axis,

a central hub integral with and connected to said weight bodies for joint rotation of said bodies and said hub,

and wherein said weight bodies extend radially outward from said hub and said bodies move in a generally radial direction relative to said hub in response to said rotation,

a frame connected to and rotatable with said hub and engaging said weight bodies so that said weight bodies react against said frame in moving radially outward and move said hub as a result of said reaction,

a switch adjacent to and engageable by said one-piece member for actuation by said one-piece member as a result of said relative movement,

and means for connecting said one-piece member to and 'for rotation with a source of rotation.

2. The centrifugal switch of claim 1 including spring means engaging and biasing said hub in an axial direction,

and means on said frame dening an axially facing surface engaging each of said bodies so that said bodies,

in moving radially outward, react against said axial surface and move said hub axially against said bias as result of said reaction.

3. A centrifugal switch arrangement comprising, in combination,

a one-piece member including a plurality of angularly spaced weight bodies disposed about an axis,

a central hub integral with and connected by a web to each of said weight bodies for joint rotation of said bodies and said hub,

and wherein said weight bodies extend radially from said hub and said bodies move in a generally radial direction relative to said hub in response to said rotation,

5 a frame connected to and rotatable with said one-piece member, said frame including means dening an axially facing surface engaging each of said bodies so that said bodies react against said frame in moving radially outward and move said hub axially as a result of said reaction,

a switch adjacent to and engageable by said one-piece member for actuation by said one-piece member as a result of said relative movement,

and means for connecting said one-piece member to and lo for rotation with a source of rotation.

4. A centrifugal switch arrangement comprising, in

combination,

a one-piece member including a plurality of angularly spaced weight bodies disposed about an axis,

a central hub integral with and connected by a web to each of said weight bodies for joint rotation of said bodies and said hub,

and wherein said weight bodies extend radially from said hub and said bodies move in a generally radial direction relative to said hub in response to said rotation,

a frame having a central portion in general alignment with said hub, said frame also including arms connected to said central portion and having portions spaced radially outward from said central portion and means on Said arms dening axially facing surfaces,

said bodies each engaging one of said axially facing surfaces so that said bodies react against said axially facing surfaces in moving radially outward and move said hub axially against said bias as a result of said reaction,

a switch adjacent to and engageable by said one-piece member for actuation by said one-piece member as a result of said relative movement,

and means for connecting said one-piece member to and for rotation with a source of rotation.

5. The centrifugal switch of claim 4 wherein said hub includes an axially extending portion,

and wherein said frame includes a plurality of angularly spaced axially extending portions engaging said axially extending portion of said hub to guide axial movement of said hub.

6. The centrifugal switch of claim S wherein said hub engages said switch,

and4 including spring means engaging and biasing said hub in an axial direction into engagement with said switch and in opposition to said reaction.

5 "7. The centrifugal switch of claim 6 wherein said onepiece member is made of polypropylene.

References Cited UNITED STATES PATENTS 6() 2,644,683 7/1953 Tamm 200--80 X 2,544,791 3/1951 Hunt 200-80 X 2,426,840 9/1947 Nye et al 200-80 ROBERT K. SCHAEFER, Primary Examiner H. J. HoHAUsER, Assistant Examiner 

